Today while cleaning I found a crab under the washing machine, it was …

Today while cleaning I found a crab under the washing machine, it was good and quite strong. I don't use crabs. My niece visited me in summer, she wrote to her today with this question, she didn't have such a crab. I exclude facts of infidelity My husband works (14 days), by the way he was at home only 8 days in the whole month, he went on overtime, and today morning I was doing shift work. I am not working and almost always stay at home. I don't have daughters, I am a mother of two sons. Where did this crab come from then? My sister immediately said that it was an infidelity.